Pectin jelly compositions



Patented Dec. .512, lgfiii pitgrail PECTIN JELLY COMPOSITIONS Charles W.Kaufman, Tenafly, N. J assignor to General Foods Corporation, New York,N. Y., a corporation of Delaware No Drawing. Application March 18, 1946,Serial No. 655,368

- Claims.

This invention relates to pectin jelly compositions and moreparticularly to such compositions of the low-sugar type in which thejellies contain little or no sugar.

For a long time it was believed that pectin jellies could not be madewithout a relatively large amount of sugar, the minimum content ofsoluble solids (mostly sugar) being variously placed between 40% and 50%and the usual fruit jelly containing 60-65%. However, it has been foundcomparatively recently that pectin which has equivalent or combiningweight determined by standard methods. Pectins useful for makinghigh-sugar fruit jellies of the first mentioned type arehigh-equivalent-weight pectins having an equivalent weight of at least400 and ranging upward to about 1000. On the other hand, pectins usefulfor making low-sugar jellies are lowequivalent-weight pectins having anequivalent weight of from 250 to 350.

It should be understood that while the pectins may be in a partial stateof neutralization for better keeping qualities, the stated equivalentweight values are the equivalent weights of the free acids. Also pectinsprepared by methods such as alcohol precipitation, for example, ofteninclude substantial amounts of precipitated organic non-pectinousmaterial. This so-called ballast material may cause the apparentequivalent weight of the sample to be as much as -25% higher than thetrue equivalent weight of the pectin when properly purified, as forexample by precipitation from solution by metal ions. In such cases thestated equivalent weight values are the true equivalent weights of thepure pectinic acid fractions.

it has been observed that such low-sugar pectin jellies are much moresusceptible to syneresis or weeping than high-sugar jellies. Syneresiscan best be described as a shrinkage of the gel structure withconsequent separation of part of the water and its appearance on thesurface of the gel. All pectin jellies are susceptible to syn-- eresisto some extent, but high-sugar pectin jellies do not exhibit syneresisto any great degree if properly prepared. With low-sugar jellies, on theother hand, the usual precautions are insufficient to reduce syneresisto an extent where it is no longer detectable or objectionable, which isespecially true if little or no sugar is used in the jellies.

The object of the present invention is to minimize syneresis inlow-sugar pectin jellies and particularly in such jellies which arecanned or otherwise sealed for shipment or storage for relatively longperiods of time.

I have discovered that the syneresis which develops in low-sugar pectinjellies may be materially reduced by using, in addition to thelowequivalent-weight pectin which forms the jelly, a certain amount ofhigh-equivalent-weight pectin. At the low sugar concentrationscontemplated, the latter pectin appears not to participate appreciablyin the bonding or other action involved in the formation of the jellies,but does have a definite and important effect in minimizing orpreventing syneresis. Such relatively inert pectin may be employed withsubstantially equal effectiveness whether the low-equivalentweightpectin is caused to gel by the presence of alkaline-earth ions or ofother metallic ions such as aluminum, irons, manganese or nickel. Iprefer, however, to employ edible calcium or magnesium salts for thepurpose of jellification. Also any high-equivalent-weight pectin can beused, but I prefer to use pectins having equivalent weights between 400and 600 because of their greater viscosity. The high andlow-equivalentweight pectins may be obtained from any of the usualsources, for example, citrus peel and apple pomace.

It is known that the demethoxylation of pectin yields pectinic acids ofdifferent degrees of demethoxylation rather than a single pectinic acid.In a given specimen of demethoxylated pectin, these different pectinicacids are very difficult to separate. Their presence can be determinedby hydrolysis.

cataphoretic analysis using for example the socalled Tiselius apparatus,but the equivalent weight of such a specimen, when determined in theusual manner, is a definite value representing an average of thedifferent pectinic acids present. It is proper to regard such a specimenas pectinic acid identifiable by its measured equivalent weight, and thevalues of 250 to 350 for low-equivalent-weight pectin, as well as theminimum value of 400 for high-equivalent-weight pectin, relate to suchmeasured equivalent weights. Nevertheless a low-equivalent-weight pectinhaving a measured equivalent weight be tween 250 and 350 may actuallycomprise pectinic acids having equivalent weights ranging from less than250 to more than the minimum value of 400 specified forhigh-equivalent-weight pectin.

The spread of pectinic acids in any pectin depends on the kind ofhydrolysis by which it was demothoxylated, e. g., hydrolysis by acid,hydrolysis by alkali, or enzymatic hydrolysis under conditions of slightacidity. This spread is least in pectin demothoxylated by acidhydrolysis and greatest in pectin demethoxylated by enzymatic It hasbeen observed that low-sugar jellies made with low-equivalent-weightpectin produced by alkali and enzymatic hydrolysis exhibit less tendencytoward syneresis than aciddemethoxylated pectins. This now appears to bedue to the greater spread of pectinic acids in the former types ofpectin, i. e., to an appreciable proportion of high-equivalent-weightpectinic acid, and also to the fact that the jellying power of suchpectins is low so that they must be used in larger amounts to effectjellification than acid-hydroylzed pectin. Hence a smaller amount ofadded high-equivalent-weight pectin is required for syneresis reduction,and the ratio of added high-equivalent-weight pectin tolowequivalent-weight pectin is less, than in the case of acid-hydroylzedpectin, but the actual amounts of high-equivalent-weight pectinic acidare comparable. I prefer to use acid-hydrolyzed low-equivalent-weightpectin for jellification and to admix it with the proper proportion ofhigh-equivalent-weight pectin for syneresis reduction.

Similarly, once separately demethoxylated pectins oflow-equivalent-weight and high-equivalent-weight has been admixed, theycan not be separated by ordinary equivalent weight determinationsbecause the mixture will have a single definite equivalent weight value.For example, a mixture of 300 equivalent weight pectin and 600equivalent weight pectin would have an intermediate equivalent weightwhen determined by standard methods, the value of which would depend onthe relative proportions of the pectins. However, the presence of thetwo pectins as components of the mixture can readily be determined byother methods such as electrophoretic analysis in the Tiselius apparatus(for a description of this apparatus and its operation see Theelectrophoretic study of proteins and related substances by Duncan A.MacInnes and Lewis G. Longsworth, Alexander's Colloid Chemistry, vol. 5,Reinhold Publishing Corporation, 1944, pgs. 387-411, inclusive).

The reduction in syneresis is proportional to the concentration ofhigh-equivalent-weight pectin employed in making the jellies, butexcessive quantities of such relatively inert pectin may adverselyaffect the texture and quality of the jellies. The optimum amount ofhigh-equiv- Ill) 4 alent-weight pectin is that which will effectivelyminimize syneresis without unduly affecting the character of thejellies, but this optimum amount depends on several factors and may varywidely under different conditions as explained hereinafter.

By way of illustration, when using low-equivalent-weight pectin obtainedby acid hydrolysis and high-equivalent-weight pectin of comparativelyhigh grade, the high-equivalent-weight pectin is best employed in theproportion of 10 to 20% of the low-equivalent-weight pectin, providedthe proportion of sugars and other dissolved solids is about 20 to 40%,as in the case of jellied fruit salads. On the other hand, in the caseof aspic, madrilenes, consommes and other compositions containing arelatively low proportion of dissolved solids, say 5 to 15%, the optimumproportion of high-equivalent-weight pectin appears to be of the orderof 20 to 30% of the low-equivalent-weight pectin. It is to beunderstood, however, that the invention is in no way limited to thesespecified proportions of high-equivalent-weight pectin inasmuch assmaller or greater proportions may be optimum under other conditions.Also, it may be desirable to increase the extent of the reduction insyneresis by increasing the proportion of highequivalent-weight pectinabove the optimum, though in general it should not exceed the proportionof low-equivalefit-weight pectin.

The amount of high-equivalent-weight pectin to be used in a givenlow-sugar pectin jelly product is also dependent on the grade of thepectin in the same manner as if it were used in the preparation of ahigh-sugar jelly For example, 300 grade pectin is about twice as viscousas and can thus be used in approximately half the amount of gradepectin.

Suspended solids such as those present in jellied fruit and vegetablesalads have been found to be without effect on syneresis and, hence, onthe amount of high-equivalent-weight pectin required to minimizesyneresis. On the other hand, the presence of dextrins and sugars insolution has been found to have a very pronounced effect on the requiredamount of high-equivalent-weight pectin, which is reduced in proportionto the concentration of such solubles. The amount ofhigh-equivalent-weight pectin may be similarly affected by otherdissolved solids which are apt to be contained in jellied products.

I have also found that low-sugar jellies exhibit maximum syneresis atcertain pH values depending on the amount of metal ion employed forjelllfication. In a series of tests on tomato aspic, for example, it wasfound that when the amount of calcium was 1.77 times the amounttheoretically necessary to fully combine with the jellifying pectin,maximum syneresis occurred at a pH of 4.1. In another series, in whichthe amount of calcium was 0.75 times the theoretical amount, maximumsyneresis occurred at a pH of 3.4. If possible, low-sugar jellies shouldbe so prepared as to avoid conditions leading to maximum syneresis,thereby permitting economy to be effected in the amount ofhigh-equivalent-weight pectin employed for syneresis reduction.

Buffer salts, such as the alkaline citrates, phosphates, acetates, etc.,do not of themselves affect the amount of high-equivalent-weight pectin,but do so indirectly because of their effect on pH.

The benefits which may be derived from the invention are illustrated bythe following examples, in which tomato aspic was prepared with andwithout the addition of high-equivalent- Each jelly contained 1.77 timesthe theoretical amount of calcium and was measured to have a pH of 4.1so that its tendency toward syneresis was maximum, thereby permitting amore precise evaluation of the different degrees of syneresis.

In preparing the jellies, the tomato juice, spice, citric acid, andpectins were mixed, and the mixtures brought to a boil. The calciumphosphate, dispersed in 5 cc. of water, was then added and, after a fewhours, the jellies set. The purpose of adding the calcium phosphate inthe form of a dispersion in water was to prevent discontinuous particlesof calcium pectinate from forming in the jellies.

The jellies were sliced to promote syneresis and, in this form, allowedto stand for five hours in a covered Buchner funnel in which the air wasmaintained saturated with humidity to prevent drying of the jellies. Therespective amounts of exudate were determined by loss in weight of thejellies and were 5.4% in the case of the control jelly and 3.3% in thecase of the improved jelly, a reduction of 40%. The degree of syneresisin the control jelly is considered excessive, whereas that in theimproved jelly is regarded as being moderate and readily tolerated incommercial production. A greater reduction would have been obtained byincreasing the proportion of high-equivalent-weight pectin, butconsiderations of cost and effect on the finished jelly, as well as theacceptability of the 40% reduction in syneresis, made it desirable tolimit the amount or high-equivalent-weight pectin used.

The following examples illustrate the progressive reduction in syneresisaccomplished by increasing amounts of high-equivalent-weight pectin.Four jellies were prepared each of which contained the followingingredients:

Grams Tomato juice 500 Salt 3.75 Citric acid 1.05 Tricalcium phosphate1.50 310 equivalent weight pectin (acid demethoxylated) 3.10

In addition, the four jellies contained the following amounts of 400equivalent weight pectin Jelly 4i 2.90

The jellies were cut into small cylinders of about inch in height andinch diameter.

These cylinders were placed upright on blotting paper and allowed tostand for three hours on such paper in covered Petri dishes. Thecomparatively small spaces in which the cylinders were confined resultedin negligible evaporation of moisture. The difierences between totalareas of stain and cylinder area were taken as a measure of the relativeamounts of exudate absorbed by the blotting paper. The following tablegives the net areas in square inches and the jelly strengths of the fourjellies as measured by the Bloom gelometer:

Jelly strength Net Area rnanufacturer. It will be understood that therpression jelly composition as used in the claims is intended to coversuch dry mixtures, which can be used to prepare jellies by adding thenecessary fruits, vegetables, tomato juice,v

soup stock, etc., as well as the finished jellies which are prepared bythe housewife or which are sold to her in cans or other containers.

It will be further understood that the expression low-sugar, when usedto qualify such jelly compositions, is meant to designate compositionsin which gelation occurs by virtue of the interaction of metal ions withpectin of a low degree of esterification, and in which sugar playssubstantially no role in contrast to the usual jellies wherein certainminimum concentrations of sugar are required for gelatin.

What is claimed is:

l. A pectin jelly composition of the low-sugar type comprising a mixtureof two pectinous ingredients, the jelliflcation ingredient consisting oflow-equivalent-weight pectin capable of forming a jelly of less than 30%soluble solids, the other pectinous ingredient consisting of a smalleramount of high-equivalent-weight pectin that does not jellify with lessthan 30% soluble solids, said other ingredients reducing syneresis inthe finished jelly.

2. A pectin jelly composition of the low-sugar type comprising a mixtureof two pectinous ingredients, the jellification ingredient consisting ofpectin having an equivalent weight between 250 and 350, the otherpectinous ingredient consisting of a smaller amount of pectin having anequivalent weight above 400 for reducing syneresis in the finishedjelly.

3. A pectin jelly composition of the low-sugar type comprising a mixtureof two pectinous ingredients, the jellification ingredient consisting ofpectin having an equivalent weight between 250 and 350, the otherpectinous ingredient consisting of a smaller amount of pectin having anequivalent weight between 400 and 600 for reducing syneresis in thefinished jelly.

i. A pectin jelly composition of the low-sugar type comprising a mixtureof two pectinous ingredients and an edible salt of a metal of the groupconsisting of calcium and magnesium, the jellification ingredientconsisting of low-equiva-= 7. lent-weight pectin capable of forming a.jelly of less than 30% soluble solids, the other pectinous ingredientconsisting of a smaller amount of high-equivalent-weight pectin thatdoes not jelliiy with less than 30% soluble solids, said otheringredient reducing syneresis in the finished jelly.

5. A pectin jelly composition of the low-sugar type comprising a mixtureof two pectinous ingredients and an edible salt of a metal or the groupconsisting of calcium and magnesium, the jelliflcation ingredientconsisting of pectin having an equivalent weight between 250 and 350,the other pectinous ingredient consisting of a smaller amount of pectinhaving an equilavent weight above 400 for reducing syneresis in thefinished jelly.

6. A pectin jelly composition of the low-sugar type comprising a mixtureof two pectinous ingredients and an edible salt of a metal of the groupconsisting of calcium and magnesium, the jellification ingredientconsisting of pectin having an equivalent weight between 250 and 350,the other pectinous ingredient consisting of a smaller amount of pectinhaving an equivalent weight between 400 and 600 for reducing syneresisin the finished jelly.

'7. A pectin jelly composition of the low-sugar type comprising amixture of two pectinous ingredients, the jellification ingredientconsisting of low-equivalent-weight pectin capable of forming a jelly ofless than 30% soluble solids, the other pectinous ingredient consist'ngof highequivalent-weight pectin that does not jellify with less than 30%soluble solids in the proportion of -20% by weight of the jellificationingredient.

8. A pectin jelly composition of the low-sugar type comprising a mixtureof two pectinous in- 8 gredients, the jellification ingredientconsisting of pectin having an equivalent weight between 250 and 350,the other pectinous ingredient consisting of pectin having an equivalentweight above 400 in the proportion of 520% by weight of thejellification ingredient.

9. A pectin jelly composition of the low-sugar type comprising a mixtureof two pectinous ingredients and an edible salt of a metal of the groupconsisting of calcium and magnesium, the jellification ingredientconsisting of pectin having an equivalent weight between 250 and 350,the other pectinous ingredient consisting of pectin having an equivalentweight above 400 in the proportion of 23-20% by weight of thejellification ingredient.

10. A pectin jelly composition of the low-sugar type comprising amixture of two pectinous ingredients and an edible salt of a metal ofthe group consisting of calcium and magnesium, the jellificationingredient consisting of pectin having an equivalent weight between 250and 350, the other pectinous ingredient consisting of Dectin having anequivalent weight between 400 and 600 in the proportion of 5-20%. byweight of the jellification ingredient.

CHARLES W. KAUFMAN.

- REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,997,615 Wallerstein et al. Apr.16, 1935 2,334,281 Olsen et al Nov. 16, 1943 2,358,430 Willaman et a1Sept. 19, 1944 2,369,846 Olsen et al Feb. 20, 1945

1. A PECTIN JELLY CORPORATION OF THE LOW-SUGAR TYPE COMPRISING AMIXTUREOF TWO PECTINOUS INGREDIENTS, HE JELLIFICATION INGREDIENT CONSISTING OFLOW-EQUIVALENT-WEIGHT PECTIN CAPABLE OF FORMING A JELLY OF LESS THAN 30%SOLUBLE SOLIDS, THE OTHER PECTINUOUS INGREDIENT CONSISTING OF A SMALLERAMOUNT OF HIGH-EQUIVALENT-WEIGHT PECTIN THAT DOES NOT JELIFY WITH LESDSTHAN 30% SOLUBLE SOLIDS, SAID OTHER INGREDIENTS REDUCING SYNERESIS INTHE FINISHED JELLY